CULTIVATION 335 



The mode of infection is through, the respiratory tract. 

 Only a small number of the spores inspired are able to reach 

 the alveoli, the greater number of them being arrested in the 

 tracheal and bronchial secretions. Hildebrant has shown that, 

 having reached the alveoli, they penetrate the epithelial lining 

 without difficulty. Both animals and man seem to possess 

 immunity to intestinal infection. Renon has produced it only 

 a few times experimentally. 



The aspergillus does not form toxin. Its pathogenic 

 power is due entirely to lesions produced by the masses of 

 mycelium which causes a necrosis of the cells and a leucocytic 

 reaction which diminishes the functions of the organs, the 

 final result being an enfeebled condition of the animal and a 

 lessened resistance to hurtful influences. When fruit hyphae 

 can form, the myriads of spores given off by them may be 

 carried to other parts of the organ. In this way the foci 

 rapidly multiply and practically the entire organ becomes 

 invaded. The opinion held by some authors that in the mould 

 mycoses there is "no fructification or actual multiplication" of 

 the infected agent and that the '"number of the diseased foci 

 corresponds exactly with the number of spores introduced," 

 is erroneous both for the disease naturally contracted as well as 

 for the experimental form. In the produced lesions, fruit 

 formation of the fungus is exceptional. It has been observed 

 by Renon to take place only where there is full communication 

 with the air. It has been observed only in the lung. It is 

 extremely rare for aspergillosis to pass from one animal to 

 another. The infection can only take place with the spores. 



Pneumonomycosis in cattle. Recently Pearson and Ravenel 

 have described a very interesting case of pneumonomycosis in 

 a cow due to A. fumigatus. As this seems to be the only care- 

 fully described case in this species of animals listed in this 

 country their description of the symptoms and lesions is very 

 largely incorporated here. The case was in a Jersey cow six 

 years old. She had been in poor condition for six months 

 prior to bringing her to the Veterinary Hospital where she was 

 tested with tuberculin with no reaction. At this time she did 



Digitized by Microsoft® 



